The specific aim of this proposal is to determine the efficacy of 4 regimens of medical therapy in the treatment and prevention of disease progression of benign prostatic hyperplasia. The 4 regimens are: 1) doxazosin; 2) finasteride; 3) doxazosin + finasteride, and 4) placebo. As part of a large, double-blind, randomized, cooperative trial this Clinical Center will evaluate, treat, and closely monitor 200 male volunteers of all races. The patients will be recruited into the study over 2 years and monitored for an additional 4 years. Patient eligibility criteria require an age of 50 years or greater, a uroflow between 4 and 15 ml/sec, and an AUA symptom score index of 8 or greater. End points for analysis include the occurrence of urinary retention, renal insufficiency, urinary tract infection, incontinence, and increase in American Urological Association symptom score index. This Clinical Center will analyze further economic costs of the treatment arms in a double-blind manner. The cooperative protocol has been developed following a Pilot Study and is subject to modifications by the Steering Committee. This Clinical Center will submit protocol data expeditiously to the Data Coordinating Center which will implement procedures for data audit and quality control procedures.